6,571 research outputs found

    Targeting telomerase for cancer therapeutics

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    One of the hallmarks of advanced malignancies is continuous cell growth and this almost universally correlates with the reactivation of telomerase. Although there is still much we do not understand about the regulation of telomerase, it remains a very attractive and novel target for cancer therapeutics. Several clinical trials have been initiated, and in this review we highlight some of the most promising approaches and conclude by speculating on the role of telomerase in cancer stem cells

    Measurements at low energies of the polarization-transfer coefficient Kyy' for the reaction 3H(p,n)3He at 0 degrees

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    Measurements of the transverse polarization coefficient Kyy' for the reaction 3H(p,n)3He are reported for outgoing neutron energies of 1.94, 5.21, and 5.81 MeV. This reaction is important both as a source of polarized neutrons for nuclear physics experiments, and as a test of theoretical descriptions of the nuclear four-body system. Comparison is made to previous measurements, confirming the 3H(p,n)3He reaction can be used as a polarized neutron source with the polarization known to an accuracy of approximately 5%. Comparison to R-matrix theory suggests that the sign of the 3F3 phase-shift parameter is incorrect. Changing the sign of this parameter dramatically improves the agreement between theory and experiment.Comment: 12 pages, RevTeX, 5 eps figures, submitted to Phys. Rev.

    Modelling Users Feedback in Crowd-Based Requirements Engineering: An Empirical Study

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    Most enterprises operate within a complex and ever-changing context. To ensure that requirements keep pace with changing context, users’ feedback is advocated to ensure that the requirements knowledge is refreshed and reflects the degree to which the system meets its design objectives. The traditional approach to users’ feedback, which is based on data mining and text analysis, is often limited, partly due to the ad-hoc nature of users’ feedback and, also, the methods used to acquire it. To maximize the expressiveness of users’ feedback and still be able to efficiently analyse it, we propose that feedback acquisition should be designed with that goal in mind. This paper contributes to that aim by presenting an empirical study that investigates users’ perspectives on feedback constituents and how they could be structured. This will provide a baseline for modelling and customizing feedback for enterprise systems in order to maintain and evolve their requirements

    Modeling canopy-induced turbulence in the Earth system: a unified parameterization of turbulent exchange within plant canopies and the roughness sublayer (CLM-ml v0)

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    Land surface models used in climate models neglect the roughness sublayer and parameterize within-canopy turbulence in an ad hoc manner. We implemented a roughness sublayer turbulence parameterization in a multilayer canopy model (CLM-ml v0) to test if this theory provides a tractable parameterization extending from the ground through the canopy and the roughness sublayer. We compared the canopy model with the Community Land Model (CLM4.5) at seven forest, two grassland, and three cropland AmeriFlux sites over a range of canopy heights, leaf area indexes, and climates. CLM4.5 has pronounced biases during summer months at forest sites in midday latent heat flux, sensible heat flux, gross primary production, nighttime friction velocity, and the radiative temperature diurnal range. The new canopy model reduces these biases by introducing new physics. Advances in modeling stomatal conductance and canopy physiology beyond what is in CLM4.5 substantially improve model performance at the forest sites. The signature of the roughness sublayer is most evident in nighttime friction velocity and the diurnal cycle of radiative temperature, but is also seen in sensible heat flux. Within-canopy temperature profiles are markedly different compared with profiles obtained using Monin–Obukhov similarity theory, and the roughness sublayer produces cooler daytime and warmer nighttime temperatures. The herbaceous sites also show model improvements, but the improvements are related less systematically to the roughness sublayer parameterization in these canopies. The multilayer canopy with the roughness sublayer turbulence improves simulations compared with CLM4.5 while also advancing the theoretical basis for surface flux parameterizations

    Effects of Bacterial Lipopolysaccharide on Plasma Corticosterone Concentrations and Body Temperatures of New Zealand Rabbits (Oryctolagus cuniculus)

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    Twelve New Zealand rabbits were injected with Salmonella typhosa endotoxin, 10 ng/kg b.w. ,via an auricular marginal vein and the effects of the pyrogen on the rectal temperatures and plasma corticosterone concentrations of these animals were observed. Our data showed significant increases of the core temperatures from the normal 39.3 +/- 0.18 to 40.9 +/- 0.43 C (p \u3c 0.001). Radioimmunoassay results of the plasma corticosterone levels were 5.76 +/- 3.7 ug/100 ml in the pre-injection blood samples and 9.02 +/- 3.7 ug/100 ml in the plasmas obtained from the animals, one hour after the pyrogen was administered. The increase of corticosterone was significant (

    Bose-Einstein Condensation of Long-Lifetime Polaritons in Thermal Equilibrium

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    Exciton-polaritons in semiconductor microcavities have been used to demonstrate quantum effects such as Bose-Einstein condensation, superfluity, and quantized vortices. However, in these experiments, the polaritons have not reached thermal equilibrium when they undergo the transition to a coherent state. This has prevented the verification of one of the canonical predictions for condensation, namely the phase diagram. In this work, we have created a polariton gas in a semiconductor microcavity in which the quasiparticles have a lifetime much longer than their thermalization time. This allows them to reach thermal equilibrium in a laser-generated confining trap. Their energy distributions are well fit by equilibrium Bose-Einstein distributions over a broad range of densities and temperatures from very low densities all the way up to the threshold for Bose-Einstein condensation. The good fits of the Bose-Einstein distribution over a broad range of density and temperature imply that the particles obey the predicted power law for the phase boundary of Bose-Einstein condensation
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